package protectjava.jsp;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
@WebServlet(name = "UploadServlet")
public class UploadServlet extends HttpServlet {
//上传文件存储目录
    private static final String UPLOAD_DIRECTORY = "upload";

//    上传配置
    private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3 ;
    private static final int MAX_FILE_SIAZE = 1024 * 1024 * 40 ;
    private static final int MAX_REQUEST_SIZE  = 1024 * 1024 * 50 ;

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        检测是否为多媒体上传
        if (ServletFileUpload.isMultipartContent(request)){
//            如果不是则停止
            PrintWriter writer = response.getWriter();
            writer.print("Error: 表单是否包含 enctype=multipart/form-data");
            writer.flush();
            return;
        }

//        配置上传参数
        DiskFileItemFactory factory = new DiskFileItemFactory();
//        设置内存存储临界值——超过后将产生零时文件，并存储与临时文件中
        factory.setSizeThreshold(MEMORY_THRESHOLD);
//        设置临时存储目录
        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));

        ServletFileUpload upload = new ServletFileUpload(factory);

//        设置最大文件上传值
        upload.setFileSizeMax(MAX_FILE_SIAZE);

//        设置最大请求值 （包含文件和表单数据）
        upload.setFileSizeMax(MAX_REQUEST_SIZE);

//        中文处理
        upload.setHeaderEncoding("UTF-8");

//        制造临时路径来存储上传的文件
//        这个路径相对当前应用的路径
        String uploadPath = getServletContext().getRealPath("/") +
                File.separator + UPLOAD_DIRECTORY;

//        如果目录不存在则创建
        File uploadDir = new File(uploadPath);
        if (!uploadDir.exists()){
            uploadDir.mkdir();
        }

        try {
//        解析请求的内容提取文件数据
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(request);

            if (formItems != null && formItems.size() > 0){
//                迭代表单数据
                for (FileItem item : formItems){
//                    处理不在表单中的字段
                if (!item.isFormField()){
                    String fileName = new File(item.getName()).getName();
                    String filePath = uploadPath + File.separator + fileName;
                  File storeFile = new File(filePath);
//                  保存文件到硬盘
                    item.write(storeFile);
                    request.setAttribute("message","文件上传成功！");
                }

                }
            }
        }  catch (Exception e) {
            request.setAttribute("message",
                    "错误信息：" + e.getMessage());
        }
//        跳转到 message.jsp
        getServletContext().getRequestDispatcher("/html1/project/jsp/message.jsp").forward(
                request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}
